-ms-filter vs filter What's the difference?

Question

What\'s the difference between between IE\'s filter and -ms-filter properties? If I use one should I use them both? Do they do the same thing, but

Answer 1

Microsoft introduced -ms-filter to make Internet Explorer more standards-compliant (CSS 2.1 requires vendor extensions to have vendor prefix). As the syntax of original filter property is not CSS 2.1 compliant, IE8+ requires the value of the -ms-filter property to be enclosed in quotation marks.

filter: alpha(opacity=40);
-ms-filter: "alpha(opacity=40)";

-ms-filter is supported in IE8+, legacy filter property is, as far as I know, for backwards compatibility supported in all versions of Internet Explorer.

Related link: http://blogs.msdn.com/b/ie/archive/2008/09/08/microsoft-css-vendor-extensions.aspx

Please note that support for filters may be removed in IE10.